Just to put a "bow" on this topic, I put both the powered and Cabbage unit on the tracks to see how they looked after the intensity mod for the powered unit. The Cabbage unit number boards were way too dim for my liking. Even after the mod to the powered unit dropped the current 5x, the Cabbage unit number boards were much dimmer.
In for a dime, in for a dollar, so I opened it up and checked out how the number boards were powered. Turns out they're powered the same as the powered unit, with track power, a resistor, and back-to-back LED's. When I traced it out, I discovered a 22K resistor for the current limiting! Yes, that's not a typo, a 22K resistor! 
Stands to reason why they're pretty dim, they were getting less than a milliamp of power! I skywired a 5.6k resistor across the 22k, that worked pretty well. So, I replaced the 22k with a 4.7k, the same as I used in the powered unit. I used a lightly larger size resistor, the old one was a 0603 size, I used the 0805 size. This gives a bit more power handling as it's passing four times the current now. On this one I actually took the picture after the mod.
This is a different board design, it has a processor managing most of the lights, but not the number boards. The Cabbage unit also uses a version of the RCDR board and not the full RCMC of the powered units or the other dummies I've worked on. Interesting tidbit, but not important for the problem I was addressing.
What do you know, the two units now have similarly lit number boards, just the way I'd expect, job done! 
As before, be aware if you screw something up, you've probably bought it. The connectors are pretty small and pulling on the wires is the kiss of death many times, so you have to exercise caution. I use husky tweezers to work the connectors out. Obviously, soldering on these boards requires something a little more sophisticated than your typical Weller 100/140 gun as well. 
